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From a615cca1e1cc5d94a4da1fb60d0e4acfd621909f Mon Sep 17 00:00:00 2001 |
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From: =?UTF-8?q?Javier=20Gonz=C3=A1lez?= <javier@javigon.com> |
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Date: Tue, 9 Oct 2018 13:11:35 +0200 |
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Subject: [PATCH 016/145] lightnvm: pblk: fix race condition on metadata I/O |
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MIME-Version: 1.0 |
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Content-Type: text/plain; charset=UTF-8 |
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Content-Transfer-Encoding: 8bit |
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[ Upstream commit d8adaa3b86324c6186d0adf74bc256bdacfffdb6 ] |
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In pblk, when a new line is allocated, metadata for the previously |
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written line is scheduled. This is done through a fixed memory region |
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that is shared through time and contexts across different lines and |
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therefore protected by a lock. Unfortunately, this lock is not properly |
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covering all the metadata used for sharing this memory regions, |
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resulting in a race condition. |
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This patch fixes this race condition by protecting this metadata |
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properly. |
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Fixes: dd2a43437337 ("lightnvm: pblk: sched. metadata on write thread") |
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Signed-off-by: Javier González <javier@cnexlabs.com> |
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Signed-off-by: Matias Bjørling <mb@lightnvm.io> |
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Signed-off-by: Jens Axboe <axboe@kernel.dk> |
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Signed-off-by: Sasha Levin <sashal@kernel.org> |
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--- |
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drivers/lightnvm/pblk-write.c | 14 +++++++------- |
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1 file changed, 7 insertions(+), 7 deletions(-) |
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diff --git a/drivers/lightnvm/pblk-write.c b/drivers/lightnvm/pblk-write.c |
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index ee774a86cf1e..879227d584e7 100644 |
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--- a/drivers/lightnvm/pblk-write.c |
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+++ b/drivers/lightnvm/pblk-write.c |
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@@ -417,12 +417,11 @@ int pblk_submit_meta_io(struct pblk *pblk, struct pblk_line *meta_line) |
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rqd->ppa_list[i] = addr_to_gen_ppa(pblk, paddr, id); |
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} |
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+ spin_lock(&l_mg->close_lock); |
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emeta->mem += rq_len; |
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- if (emeta->mem >= lm->emeta_len[0]) { |
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- spin_lock(&l_mg->close_lock); |
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+ if (emeta->mem >= lm->emeta_len[0]) |
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list_del(&meta_line->list); |
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- spin_unlock(&l_mg->close_lock); |
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- } |
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+ spin_unlock(&l_mg->close_lock); |
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pblk_down_page(pblk, rqd->ppa_list, rqd->nr_ppas); |
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@@ -491,14 +490,15 @@ static struct pblk_line *pblk_should_submit_meta_io(struct pblk *pblk, |
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struct pblk_line *meta_line; |
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spin_lock(&l_mg->close_lock); |
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-retry: |
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if (list_empty(&l_mg->emeta_list)) { |
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spin_unlock(&l_mg->close_lock); |
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return NULL; |
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} |
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meta_line = list_first_entry(&l_mg->emeta_list, struct pblk_line, list); |
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- if (meta_line->emeta->mem >= lm->emeta_len[0]) |
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- goto retry; |
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+ if (meta_line->emeta->mem >= lm->emeta_len[0]) { |
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+ spin_unlock(&l_mg->close_lock); |
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+ return NULL; |
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+ } |
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spin_unlock(&l_mg->close_lock); |
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if (!pblk_valid_meta_ppa(pblk, meta_line, data_rqd)) |
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-- |
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2.19.1 |
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